Search Publications
Multi-epoch observations with high spatial resolution of multiple T Tauri systems
Ábrahám, Péter; Brandner, Wolfgang; Köhler, Rainer +4 more
Context. In multiple pre-main-sequence systems the lifetime of circumstellar discs appears to be shorter than around single stars, and the actual dissipation process may depend on the binary parameters of the systems.
Aims: We report high spatial resolution observations of multiple T Tauri systems at optical and infrared wavelengths. We deter…
X-ray survey of the North-America and Pelican star-forming complex (NGC 7000/IC 5070)
Damiani, Francesco; Pillitteri, Ignazio; Prisinzano, Loredana
Aims: We present the first extensive X-ray study of the North-America and Pelican star-forming region (NGC 7000/IC 5070), with the aim of finding and characterizing the young population of this cloud.
Methods: X-ray data from Chandra (four pointings) and XMM-Newton (seven pointings) were reduced and source detection algorithm applied to …
Nuclei of dwarf spheroidal galaxies KKs 3 and ESO 269-66 and their counterparts in our Galaxy
Sharina, M. E.; Kniazev, A. Y.; Shimansky, V. V.
We present the analysis of medium-resolution spectra obtained at the Southern African Large Telescope for nuclear globular clusters (GCs) in two dwarf spheroidal galaxies (dSphs). The galaxies have similar star formation histories, but they are situated in completely different environments. ESO 269-66 is a close neighbour of the giant S0 NGC 5128.…
The Unusually High Halo Concentration of the Fossil Group NGC 6482: Evidence for Weak Adiabatic Contraction
Buote, David A.
Although fossil galaxy systems are thought to be very old, and thus should possess above-average halo concentrations, typically fossils have unexceptional concentrations of their masses. We revisit the massive isolated elliptical galaxy/fossil group NGC 6482 for which previous X-ray studies of a modest Chandra observation obtained a very uncertain…
Phase Relations between the Sunspot Numbers and Total Solar Irradiance
Xu, J. C.; Xie, J. L.; Qu, Z. N.
Understanding the effect of sunspot activities on the variations in the total solar irradiance (TSI) is essential for the interpretation of the variability of TSI as well as its reconstruction. Phase relations between the sunspot numbers (SN) and two TSI composite data are investigated. It is found that TSI and SN are positively correlated, and th…
The effect of CO2 on gases trapping in cometary ices
Bar-Nun, A.; Laufer, D.; Ninio Greenberg, A.
Water vapour and CO2 have been detected as the major volatile constituents in the coma of comet 67P/Churyumov-Gerasimenko, by ROSINA (Rosetta Orbiter Spectrometer for Ion and Neutral Analysis) onboard the Rosetta spacecraft. In this paper, we describe experimental results showing the influence of CO2 trapping in amorphous wat…
INTEGRAL Observations of GW170104
Sunyaev, R.; Hanlon, L.; Mereghetti, S. +16 more
We used data from the International Gamma-Ray Astrophysics Laboratory (INTEGRAL) to set upper limits on the γ-ray and hard X-ray prompt emission associated with the gravitational-wave event GW170104, discovered by the Laser Interferometer Gravitational-wave Observatory (LIGO)/Virgo collaboration. The unique omnidirectional viewing capability of th…
Validation of a scaling law for the coronal magnetic field strength and loop length of solar and stellar flares
Namekata, Kosuke; Shibata, Kazunari; Watanabe, Kyoko +2 more
Shibata and Yokoyama (1999, ApJ, 526, L49; 2002, ApJ, 577, 422) proposed a method of estimating the coronal magnetic field strength (B) and magnetic loop length (L) of solar and stellar flares, on the basis of magnetohydrodynamic simulations of the magnetic reconnection model. Using the scaling law provided by Shibata and Yokoyama (1999, ApJ, 526,…
The Survey of Lines in M31 (SLIM): The Drivers of the [C II]/TIR Variation
Schinnerer, Eva; Groves, Brent; Glover, Simon +7 more
The ratio of the [C II] 158 µ {{m}} emission line over the total infrared emission (TIR) is often used as a proxy for the photoelectric (PE) heating efficiency ({ɛ }{PE}) of the far-ultraviolet (FUV) photons absorbed by dust in the interstellar medium. In the nearby galaxy M31, we measure a strong radial variation of [C II]/TIR th…
On the link between martian total ozone and potential vorticity
Holmes, James A.; Lewis, Stephen R.; Patel, Manish R.
We demonstrate for the first time that total ozone in the martian atmosphere is highly correlated with the dynamical tracer, potential vorticity, under certain conditions. The degree of correlation is investigated using a Mars global circulation model including a photochemical model. Potential vorticity is the quantity of choice to explore the dyn…